It seems you are starting with 5,2 oc which may be too much for your chip. Start with 5 GHz following one of the many overclocking guides done on asus z390 boards. Use bios 0601 or newer.
new rig 2019:
Intel 9900k >5ghz | Asus Maximus XI Gene | Eisbaer 360 LT (custom loop in progress) | bequiet! Dark Base 700 white edition | RAM: 16B team group Nighthawk 4000mhz | Gigabyte RTX 2070 OC white | Storage: Intel Optane 900p 280GB + Samsung 970 evo plus 1TB + WD Red 3TB | Corsair HX850i | Benq BL3200PT 1440p | 1Gbit ftth |